(a) Field of the Invention
The present invention relates to a variable valve device that lifts valves for opening an intake port and an exhaust port that are connected to a combustion chamber, and varies the lift amount so as to improve efficiency depending on driving conditions of an engine.
(b) Description of the Related Art
Various methods for varying the movement of a valve in an internal combustion engine are well known.
Typically, a conventional method uses a camshaft, a rocker arm, or a finger follower to control the movement of the valve.
When a conventional variable valve device is used in an internal combustion engine, the object thereof is improving the fuel efficiency, and there is a known method that uses a profile of a cam to directly control the lift of the valve and there is a known method that uses lost motion to control the lift of the valve.
A hydraulic lash adjuster is used to reduce the gap between a valve and a swing arm on a variable valve train, and it is hard to simplify the variable valve device and the hydraulic lash adjuster.
PRIOR ART FIG. 5 is a cross-sectional view of a variable valve device. Referring to FIG. 5, the variable valve device includes a swing arm 150, a lost pin 155, a lost body 140, a roller 125, a guide pin 160, a latching pin 425, a latching spring 115, a latching cap 415, a valve 135, and a hydraulic pressure lash adjuster 120.
The latching pin 425 is inserted into the latching groove 405 that is formed at an opposite side of the lost pin 155 on the swing arm 150, and the latching spring 115 elastically presses the latching pin 425 toward the lost pin 155.
Meanwhile, the swing arm 150 rotates in a counterclockwise direction based on a support point of the hydraulic pressure lash adjuster 120 to repeatedly press the valve 135 in a lower diction and an inertial force of the latching pin 425 is formed in a left side by a high speed rotation movement of the swing arm 150, and therefore the control precision of the latching pin 425 can be deteriorated.
Further, in a case that two valves 135 are disposed and two hydraulic pressure lash adjusters 120 are disposed, a gap or a deviation is formed between the hydraulic pressure lash adjuster 120 and the swing arm 150 and the latching pin 425 can be abnormally operated by the leak of the oil.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.